声学造影剂及二次谐波成像在肝癌中应用初探
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| 时间：2009-01-09 21:19:26 来源： 作者： |
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The initial study of sonographic contrast agent and second harmonic imaging on HCC
Abstract:Purpose: This study is to evaluate microbubble based ultrasonic contrast agent and harmonic imaging on liver tumor.Methods:Before and after media (Dose was from 0.5 to 1.0 ml) were injected into peripheral veins of 22 ptients with hepatocellulor carcinoma (HCC), fundamental imaging、 color Doppler imaging and second harmonic imaging were performed.Second harmonic imaging were performed with ATL-HDI 5000 (1.7/3.4 MHz) or HP5500 (1.8/3.6 MHz). Some cases were just deteced in color Doppler sonography with Logiq500 or AU4(3.5 MHz) after media were injected. Results:Except some spot enhancement on the lesions of five cases,there were little enhancement could be noticed on liver at arterial phase.However,after portal veins were enhanced obviously,the parenchyma of livers were enhanced considerable but not of the tumors.Hypoechoic masses were well detected after administration of contrast agents.Hyperechoic masses and isohyperechoic masses were poorly detected.The media and harmonic imaging increased the echointensity of normal and tumor vessels in liver lesions,there were more vessels could be showed as well. Conclusion:Microbubble based agent is mainly to reflect the blood perfusion of liver in generally. HCC is always hypovascular in relation to the normal liver.Microbubble based agent and harmonic imaging improve the visualization of vessels.It is needed further study to show the tissue characteristics by harmonic imaging.
Key words:contrast agent; second harmonic imaging; liver tumor; blood vessel; ultrasound
近来经外周静脉注射用声学造影剂的研制取得较大进展，但该类造影剂在肝癌中的应用还较少［1］。二次谐波成像是超声技术的最新发展之一，它是利用声波在传播过程中部分能量转化为高次谐波的特性，进行非线性参量的计算机模拟成像［2］。我们用经外周静脉注射声学造影剂并行二次谐波成像，探讨它们在肝癌中的应用价值。
1 资料和方法
1.1 研究对象：22例1997年11月至1999年2月在我院肝胆外科和消化内科住院的肝癌病人，均为男性，年龄35～75岁，平均(44.6±13.2)岁。14例经手术和病理证实，8例经影像学检查和AFP等检查确诊。
1.2 声学造影剂：我院药学部提供。9例用声振型声学造影剂，该造影剂系用5%白蛋白溶液经XL2020型声振仪声振处理60秒，制成微气泡在(4.2±2.4) μm，浓度大于108/ml的造影剂。另13例用“全氟显”声学造影剂，这是一种含氟丙烷白蛋白的冻干品，临用前用生理盐水3 ml稀释并两手搓动制成，微气泡大小和浓度与声振型相似。每例均经前臂浅静脉注入造影剂0.5～1.0 ml，可重复注射，少量生理盐水在注射造影剂后冲管，以利造影剂尽快进入循环。
1.3 超声仪器及成像方法：先后采用ATL公司提供的HDI5000样机和Hewlett Packard公司提供的HP5500样机及我院购买的HP5500超声仪检查，部分病例用GE公司的Logiq500或Esaotebiomedica公司的AU4超声仪检查。HDI5000和HP5500均具备基波成像和二次谐波成像等多种功能。基波成像为3.5 MHz或4.0 MHz。HDI5000二次谐波成像的频率是1.7/3.4 MHz，HP5500二次谐波成像的频率是1.8/3.6 MHz。造影剂使用前行基波成像并定位，后改用二次谐波并注射造影剂。用录像带或光盘保存图像，回放以分析。Logiq500和AU4型超声仪成像频率是3.5 MHz，行基波成像和增强后的彩色多普勒成像。
2 结果
2.1 增强前基波成像：结节型肝癌8例，6例为低回声病灶，右后叶的1例，大小约3.4 cm×2.7 cm，界尚清，但与周围正常肝组织回声对比不甚强，余边界清晰，显示清楚；另2例呈稍高回声结节，界清。巨块型肝癌8例，肿块大小6.1～12.6 cm，6例为高回声界清包块；1例位于左半肝病灶，内部回声不均，以中高回声混杂为主，伴散在分布的类圆形低回声暗区；1例为低回声界清包块，大小约8.0 cm×7.3 cm。6例弥漫型肝癌，呈中高混合回声，边界不清，其间可见条索状低回声血管样结构。
2.2 增强后彩色多普勒成像及二次谐波成像：注射造影剂后，在门静脉主干及主要分支增强前，大部分病例肝内看不到明显增强回声，只有3例巨块型肝癌和2例弥漫型肝癌可注意到病灶有点状增强。当门静脉主干及主要分支增强后，正常肝组织才明显增强，但病灶增强不明显。
结节型病灶内部多无明显增强表现，1例“延迟扫描”(再经10秒)时出现斑片状回声增强。多数低回声病灶基波成像已显示清楚，二次谐波灰阶成像依然清晰，位于右后叶病灶，基波成像与周围正常肝组织回声对比不甚强，二次谐波成像因周边肝组织回声增强，显示更清楚，并可见周边环绕血管。2例稍高回声结节，增强后周围正常肝组织回声增强，与病灶间回声对比减弱。
8例巨块型肝癌，6例造影前呈高回声界清病灶，注射造影剂后成像周围正常肝组织回声增强，与病灶间回声对比减弱，以及病灶内部和周边出现条索状、斑片状增强回声，病灶显示不如造影前清晰，出现“肿瘤消失现象”，其中1例增强早期出现肿瘤消失现象，再经数秒后周围正常肝组织增强效应减退，但病灶仍残留增强回声。1例混合回声界不清病灶，增强后仍呈混合回声，类圆形低回声区亦无变化，术后证实有坏死液化灶。1例低回声界清病灶，注射造影剂后(仅行基波成像)病灶无明显增强，周边正常肝组织回声增强，对比增加。
6例弥漫型肝癌，注射造影剂后(1例仅行基波成像)仍呈混合回声，界仍不清，病灶内可见条状、片状增强。
应用logiq500和AU4行彩色多普勒成像者增强程度不如二次谐波成像，但结果相似。
可见，肝癌组织中应用声学造影剂增强后对低回声型病灶显示有帮助，对高回声或中高混合回声型病灶显示无益。应用造影剂早期仅少数病灶可注意到出现点状增强，多数病例是在门静脉增强后肝实质明显增强，而病灶增强不明显。有些病灶增强回声滞留时间长于正常组织。
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